ERASERS were headed for oblivion until Su Doku made them indispensable. But a new rule for tournament chess players may make them illegal, if there’s a way to enforce it.

The U.S. Chess Federation’s delegates voted last month to bring American rules into compliance with the world: A player cannot write down his move until he plays it on the board. Otherwise it is an illegal “note.”

This change was prompted in part by a technological advance, the introduction of electronic score sheets which show a video display of the position. A player writing down his move could visualize a future position.

The problem is that generation or two of American players have been taught to follow the Soviet-era practice of writing your next move down first and then reconsidering it. They don’t want to change an ingrained habit.

Critics say the new rule will inevitably lead to “You wrote it down first!” – “No, I didn’t!” fights.

Supporters say the real problem is erasers. Young players routinely write first, then erase the move. They may repeat the process several times. Some older players, who should know better, openly write down a move they have no intention of playing so that their opponent will waste time considering it. The new rule bars all this.